.mask{
    width: 100%;
    height: 100vh;
    background-color: rgba(0,0,0,.5);
    position: absolute;
    z-index: 10;
    display: none;
}
.mask-box{
    width: 500px;
    height: 200px;
    background-color: #f0f0f0;
    position: absolute;
    left: 50%;
    top: 50%;
    margin-left:-250px;
    margin-top: -100px;
    border-radius: 10px;
    overflow: hidden;
    user-select: none;
}
.mask-box .head{
    text-align: center;
    color: #f0f0f0;
    height: 40px;
    line-height: 40px;
    background: linear-gradient(to bottom, #1E9FFF, #00F7DE);
}
.mask-box p{
    text-align: center;
    margin-top: 40px;
    margin-bottom: 40px;
    font-size: 20px;
    font-weight: bold;
}
.mask-box button{
    display: block;
    margin: 0 auto;
    width: 100px;
    height: 40px;
    border-radius: 30px;
    outline: none;
    border:none;
    background: linear-gradient(to bottom, #1E9FFF, #00F7DE);
    color: #f0f0f0;
    font-size: 18px;
    cursor: pointer;
    box-shadow: 0 1px 1px 1px #ccc;
}